1. Field of the Invention
The present invention relates to a strut mount structure of a strut-type suspension for a vehicle body.
2. Discussion of the Related Art
A strut-type suspension is widely used as a suspension for a vehicle body. Such a structure is used because it is simple; that is, the wheel alignment can be accurately set because the point where the strut is fixed to the body is high and the deviation of the wheel alignment is small. Therefore, shock from a road to the body can be widely dispersed over the body, and the suspension can be light-weight since the number of members is small.
FIG. 5 shows a perspective diagram of a front part of a body 1. Here, a strut 11 which is vertically installed contains a shock absorber 15 and a coil spring 16 around the shock absorber 15. A top end of the strut 11 is fixed to and supported by the body, and a bottom end of the strut 11 is supported by the body via a lower arm 18, with a knuckle arm 17 for supporting a wheel fixed to the bottom end.
In order to secure steering stability, the strut 11 is provided with a caster angle with the top end inclined in the rear direction with respect to the bottom end when seen from the side of the vehicle, and with a strut inclination angle by the top end inclined in the inner direction of the vehicle with respect to the bottom end when seen from the front.
As shown in FIG. 6 which is an enlarged cross-section along a line VIxe2x80x94VI of FIG. 5, an upper part of the strut 11 is fixed to and supported by the main body via a strut mount unit 20. The upper part of the strut 11 has an installation hole 19a provided on a spring sheet 19 which supports a top end of a coil spring 16 and a small diameter portion 12 which fits in the installation hole 19a, forming a step. Further, a screw part 13 is formed on the top of the small diameter portion 12.
The strut mount unit 20 has a bearing housing 22 approximately in the shape of a cylinder having an upper part thereof with a smaller diameter. The bearing housing 22 holds a bearing 21 at a lower part thereof and fits with the small diameter portion 12 of the strut 11. An inner fitting 23 approximately in a cylindrical shape with the diameter gradually increasing in a downward direction has a top end caulked with the upper part of the bearing housing 22. An outer fitting 25 approximately in the shape of a cylinder has a flange 26 at the lower part. The outer fitting 25 is connected to the inner fitting 23 by a rubber portion 24 therebetween.
The strut 11 and the strut mount unit 20 are thus connected in one united body by fitting the small diameter portion 12 into the installation hole 19a provided on the spring sheet 19, inserting the small diameter portion 12 into the bearing 21, and then screwing a nut 27 on the screw part 13.
On the other hand, the top end of the strut 11 is supported by the main body at the strut mount unit 20 on a wheel apron 32, a strut tower 33, and an upper bracket 34. The wheel apron 32 forms a lateral wall of an engine room E connected with an upper frame 31 which extends in the front-to-back direction along the lateral wall. The strut tower 33 extends downward vertically between the engine room E and a part on the wheel apron 32. The upper bracket 34 is provided across the upper part of the strut tower 33 and the upper part of the wheel apron 32.
The upper bracket 34 has a strut installation hole 36a as an opening to which the upper part of the outer fitting 25 is inserted. The upper bracket 34 also has a planer portion 35. By inserting the outer fitting 25 to the strut installation hole 36a, a flange 26 of the outer fitting 25 is in contact with the lower surface of a strut mount installation portion 36. There is a connection flange part 35a in a bent form, which is contiguous with the planer part 35 and is connected to upper parts of the wheel apron 32 and the strut tower 33.
The flange 26 is brought into contact with the strut mount installation portion 36 at the lower surface thereof by insertion of the upper part of the outer fitting 25 into the strut installation hole 36a. The overlaid strut mount installation portion 36 and the flange 26 are fixed together by a bolt 38 and a nut 39, whereby the top end of the strut 11 is fixed to the main body via the strut mount unit 20. In FIG. 6, a cap 29 is provided fitting with the top of the bearing housing 22 for preventing dust and water drops from intruding into the bearing housing 22.
The front hood 40 shown in the figure covers the top of the engine room E, and is composed of an outer panel 41 and an inner panel 42 extending below the outer panel 41. The front hood 40 is fixed to and supported by the main body by front hood hinges (not shown) at the rear edge. The outer panel 41 is smoothly and continuously bent so that the outer edges thereof in the width direction are lower, and declined towards the front. The inner panel 42 is cut out at a part corresponding to the location of the strut mount unit 20. The inner panel 42, together with the outer panel 41, form a frame structure having continuous hollow cross-sections created by downwardly projected portions of the inner panel 42 as shown.
The strut mount unit 20 has a top face defined by top edges 23a and 25a of the inner fitting 23 and the outer fitting 25. The cross-section of the top face, that corresponds to a line defined by the top edges 23a and 25a when viewed from the side, crosses a central axis 11a making a right angle. The strut 11 is provided with a strut inclination angle with the top end inclined in the inner direction of the vehicle with respect to the bottom end when seen from the front, and with a caster angle (not shown) by the top end inclined in the rear direction with respect to the bottom end when seen from the side of the vehicle, in order to secure steering stability. Because of the inclination of the strut 11, the top edges 23a and 25a are inclined to have the outer edge higher than the inner edges in the car-width direction and the edges toward the front side of the vehicle are higher than the edges facing the rear of the vehicle. The planer part 35 of the upper bracket 34 is inclined to have the strut mount installation portion 36 correspond to the inclination of the strut mount unit 20. Namely, the outer side of the strut mount installation portion 36 is higher than the inner side thereof, and the front side is higher than the rear side. On the other hand, the front hood 40 is bent to have lower outer sides and a lower front side as mentioned previously. By the interaction between the inclinations of the strut mount unit 20 and the front hood 40, the minimum gap L that can be formed between the top edge of the strut mount unit 20 and a lower face of the front hood 40 is restricted.
Owing to the necessity to maintain the minimum gap L between the strut mount unit 20 and the front hood 40 satisfactorily, the shape of the front hood 40 is restricted. Hence, the restricted shape of the front hood 40 may affect the structural design freedom. Moreover, when a pedestrian comes into contact with the vehicle on the front hood 40 with a restricted deformable distance between the front hood 40 and the strut mount unit 20, there is the possibility that impact absorption effect by the deformation of the front hood 40 would not be satisfactory. Furthermore, if the strut mount unit 20 is placed at a low position to have the minimum gap L large, the effective length of the strut 11 is shortened. In this case, it would not be possible to provide as comfortable a ride.
It is therefore an object of the present invention to provide a strut mount structure wherein a minimum gap between a strut mount unit and a lower face of a front hood can be made larger in comparison to a corresponding minimum gap in a conventional strut mount structure. As a result, the shape of the front hood can be freely selected and the structural design freedom is increased. In addition, safety to a pedestrian is improved by the satisfactory deformation capability of the front hood which absorbs impact as a result of the larger minimum gap, for instance, when the pedestrian contacts with the front hood from the top.
The object of the present invention is achieved by a strut mount structure for supporting a strut to be installed in a strut tower in a vehicle body, comprising an upper bracket provided on a top of the strut tower, the upper bracket having a strut installation hole and a strut mount installation portion provided to surround the strut installation hole; and a strut mount unit having an inner fitting approximately in a cylinder shape with an inner fitting top edge, the inner fitting supporting a top end of the strut; approximately in a cylinder shape with an outer fitting top edge, and a flange connected to the strut mount installation portion by a top part of the outer fitting inserted into the strut installation hole from the back of the upper bracket; a rubber portion with a rubber top face interposed between the inner fitting and the outer fitting for connecting the inner fitting and the outer fitting together, wherein an imaginary plane defined on the outer fitting top edge and a central axis of the strut cross each other so as to define a first angle as an inner angle when viewed from the front of the vehicle body and a second angle as a front angle when viewed from the side of the vehicle body, the first angle being an obtuse angle and the second angle being an acute angle.
The object of the present invention is also achieved by a strut mount structure for supporting a strut to be installed in a strut tower in a vehicle body, comprising an upper bracket provided on top of the strut tower, the upper bracket having a strut installation hole and a strut mount installation portion provided to surround the strut installation hole; and a strut mount unit having an inner fitting approximately in a cylinder shape with an inner fitting top edge, the inner fitting supporting a top end of the strut; an outer fitting approximately in a cylinder shape with an outer fitting top edge, and a flange connected to the strut mount installation portion by a top portion of the outer fitting being inserted into the strut installation hole from the back of the upper bracket; a rubber portion with a rubber top face, interposed between the inner fitting and the outer fitting for connecting the inner fitting and the outer fitting for connecting the inner fitting and the outer fitting together, wherein the outer fitting is fixed so as to maintain an almost equal distance from any portion of the outer fitting top edge to a lower face of a front hood of the vehicle body.
The object of the present invention is also achieved by a strut mount structure for supporting a strut to be installed in a strut tower in a vehicle body, comprising an upper bracket provided on a top of the strut tower, the upper bracket having a strut installation hole and a strut mount installation portion provided to surround the strut installation hole; and
a strut mount unit having an inner fitting approximately in a cylinder shape with an inner fitting top edge, the inner fitting supporting a top end of the strut; an outer fitting approximately in a cylinder shape with an outer fitting top edge, and a flange connected to the strut mount installation portion by a top portion of the outer fitting being inserted into the strut installation hole from the back of the upper bracket; a rubber portion with a rubber top face, interposed between the inner fitting and the outer fitting for connecting the inner fitting and the outer fitting together, wherein the outer fitting top edge is inclined to have an outer side lower than an inner side of the vehicle body in a car-width direction and a front side lower than a rear side of the vehicle body in a car front-to-back direction.
Another object of the present invention is to provide the above-mentioned strut mount structure which provides further improved safety to a pedestrian even when the front hood is largely deformed when the lower face thereof is depressed to be in contact with the outer fitting top edge as a result of impact with a pedestrian locally on a part of the vehicle body, wherein the inner-fitting top edge, the outer fitting top edge and the rubber top face approximately form a single planer upper face of the strut mount unit.
A further object of the present invention is to provide the above-mentioned strut mount structure wherein automatic installation of the strut mount unit is easily carried out by a bolt runner which is effectively used in common for fastening at least one bolt which is vertically provided on a horizontal surface, wherein the flange further comprises an installation bolt which has been fixed thereto at a bolt installation portion, the strut installation portion further comprises a bolt hole perforated therein, the installation bolt inserted to the bolt hole from the back of the strut installation portion, a part of the bolt upwardly protruded from the bolt hole being connected with a nut so that the outer fitting is combined to the upper bracket, each of the bolt installation portion and the bolt hole formation portion is horizontally provided, and the installation bolt extends in a vertical direction.
Still another object of the present invention is to provide the above-mentioned strut mount structure which effectively prevents entrance of water drops, muddy water or the like scattered by wheels to an engine room without the use of an additional member, wherein the rubber portion comprises a sealing portion in one united body which seals a gap between an outer periphery of the flange and a lower face of the upper bracket.